Characterizations of Polystyrene-Based Hybrid Particles Containing Hydrophobic Mg(OH)2 Powder and Composites Fabricated by Employing Resultant Hybrid Particles

Polystyrene (PS)-based hybrid particles containing a large amount of Mg(OH)2 powder treated with methylhydrogen polysiloxane (MHS) were fabricated by a bulk and subsequent suspension two-step polymerization method. All the particles fabricated showed spherical shape and their particle sizes were about 500 μm, irrespective of the additive amount of the Mg(OH)2 powder modified with MHS (ST-1). The actual content of ST-1 powder incorporated inside each kind of hybrid particle was almost the same as that in the raw mixture, and agglomeration of ST-1 powder was hardly observed inside the hybrid particles. The compressive strength of the hybrid particles remained almost unchanged, even when the ST-1 powder content increased from 10 to 50 phr. Furthermore, a composite fabricated by employing the hybrid particles achieved homogenous distribution of ST-1 powder and showed a higher oxygen index than that of a composite fabricated by directly mixing of PS pellets and ST-1 powder.